1. Field of the Invention
The present invention relates to guiding assemblies for translatorily or rotatively carrying a moving element on a linear or rotational guide means, said moving elements having a housing with bearings for at least a set of guiding balls rotatively supported therein and said guide means being provided with guiding surfaces specifying a guiding direction, said guiding balls being placed relative to said guide means to contact the guiding surfaces and to provide a form-locked support transversely to said guiding direction.
2. Description of the Prior Art
A linear guiding assembly of the above mentioned type is disclosed in German patent publication No. 649 218, published Aug. 18, 1937 and in GB-publication No. 2 013 832. In these guiding assemblies the guide means have to be extremely precise to avoid jamming of the moving element on the guide means. Even though this condition is satisfied, any bending of the guide means by mechanical load leads to the danger of jamming. The only possibility to avoid this danger is to adjust the guiding balls such as to admit a certain amount of looseness or play of the guiding assembly. This, however, is not acceptable for many applications.
The same problem exists in a modified construction according to U.S. Pat. No. 3,407,011. Therein both of two rollers provided for supporting a round shaft are mounted with an amount of play and therefore do not provide a form-locked support transverse to the guiding direction. This bearing is not suited as a play-free guiding assembly since all its rollers are displaceably mounted and therefore lead to unexpected and foreseen reactions upon load.
French publication No. 739 913 discloses a carriage sliding on a bed having bearing balls, which are elastically displaceable such that upon loading the carriage the bearing balls are pressed into the bed, thereby raising the frictional forces to fix the carriage on the bed. In the invention, however, the frictional forces should not be dependent on the load applied.
In Swiss publication No. 326 285 finally a rotational guiding assembly is disclosed, wherein a round table is supported on balls which are mounted in an opposite table. This arrangement does not provide for a form-locking assembly transverse to the guiding direction and therefore can only be loaded from one side.